Fuel fired space heater

ABSTRACT

A fuel fired space heater directing infrared in a downward direction from a radiant confined within a combustion chamber at the lower end of an elongate inclined housing, an enlarged combustion gases discharging chamber above said combustion chamber and delivering the combustion gases to an outlet, the housing having a radiant heat discharging port beneath said combustion chamber, and a flexible panel of a material highly transmissive of infrared and also being inclined with the lower edge of the inclined panel secured to the housing adjacent the radiant heat discharging port and the upper side portion of the panel being spaced from the housing or supplied by an air intake passageway, but confronting the entire port to enclose the port and deliver combustion air downwardly along the inner face of the panel for preventing deposit of dust and delivering cool combustion air for cooling the panel and supplying air to the fuel fired radiant. Space heaters for extremely dusty spaces such as turkey houses where a substantial amount of litter is on the floor usually require an extreme amount of maintenance so as to remain functional, primarily because of the dust that must be contended with in such installations. In turkey brooders, a substantial amount of the dust is airborne of which 20 percent by weight is in continuous suspension and 80 percent is sedimentary so as to settle on everything that has a somewhat horizontal surface. Insurance and other applicable codes vary from place to place and the nature of the fuel fired heating installation will be controlled accordingly. It has been a problem to accommodate the installation codes of heaters as well as to accommodate the dust problem which is always present and which is of primary importance in the design or selection of a heater for a particular installation.

United States Patent [191 Eichenlaub Mar. 119, 1974 FUEL FIRED SPACEHEATER John E. Eichenlaub, 9321 Franklin Ave, West, Minneapolis, Minn.55426 [22] Filed: May 18, 1973 [21] App]. No.: 361,519

[76] Inventor:

Primary Examiner-William E. Wayner Assistant ExaminerWilliam E.Tapolcai, Jr. Attorney, Agent, or Firm-H. Dale Palmatier; James R.Haller [57] ABSTRACT A fuel fired space heater directing infrared in adownward direction from a radiant confined within a combustion chamberat the lower end of an elongate inclined housing, an enlarged combustiongases discharging chamber above said combustion chamber and deliveringthe combustion gases to an outlet, the

housing having a radiant heat discharging port beneath said combustionchamber, and a flexible panel of a material highly transmissive ofinfrared and also being inclined with the lower edge of the inclinedpanel secured to the housing adjacent the radiant heat discharging portand the upper side portion of the panel being spaced from the housing orsupplied by an air intake passageway, but confronting the entire port toenclose the port and deliver combustion air downwardly along the innerface of the panel for preventing deposit of dust and delivering coolcombustion air for cooling the panel and supplying air to the fuel firedradiant.

Space theaters for extremely dusty spaces such as turkey houses where asubstantial. amount of litter is on the floor usually require an extremeamount of maintenance so as to remain functional, primarily because ofthe dust that must be contended with in such installations. In turkeybrooders, a substantial amount of the dust is airborne of which 20percent by weight is in continuous suspension and 80 percent issedimentary so as to settle on everything that has a somewhat horizontalsurface.

Insurance and other applicable codes vary from place to place and thenature of the fuel fired heating installation will be controlledaccordingly. It has been a problem to accommodate the installation codesof heaters as well as to accommodate the dust problem which is alwayspresent and which is of primary importance in the design or selection ofa heater for a particular installation.

14 Claims, 11 Drawing Figures PMENTED m 1 9 $974 SHEET 1 BF 3 FIEZE3L797L4T4 PATENTEDHAR 1 9 1914 SHEEI 2 OF 3 PATENTEDHARIS m4 3797L474SHEET 3 BF 3 FUEL FIRED SPACE HEATER SUMMARY OF THE INVENTION A gasfired space heater with the flame heated radiant and combustion chamberalmost entirely enclosed except for the combustion air inlet. Aprincipal heat discharge is a radiant heat transmissive panel throughwhich infrared from the radiant is radiated. The panel is generallyhorizontal and disposed beneath the radiant to transmit infrareddownwardly, but the panel is slightly inclined whereby cool combustionair admitted into the combustion chamber at the upper edge of the panelwill rapidly sweep along the panel and downwardly to cool andcontinuously clean the panel of dust.

The radiant heat transmission panel may be concavely curved from side toside relative to the substantially flat radiant so that the portion ofthe panel confronting the center of the radiant, where the infrared ismost intense, is spaced farthest from the radiant.

The heater also incorporates a heat exchanger section with a combustiongases-carrying plenum chamber superiorily disposed relative to thecombustion cham-' ber and in open communication therewith. Because ofthe arrangement of the plenum chamber relative to the combustionchamber, combustion gases do not move back into the combustion chamber.

The heater may be completely sealed against gaseous communication withthe space being heated by exhausting from the heat exchanger to anexterior space and by also supplying air to the upper edge of the heattransmissive panel from the same exterior space which may be at theoutside of the building.

Combustion air may be supplied to the heater by a duct incorporating theheat transmissive panel as a portion of the duct. Such a duct may supplycombustion air from the exterior of the space being heated. In certaininstances it may be desirable to exhaust the combustion gases directlyinto the space being heated, whereupon the space must be maintainedunder negative or neutral pressure, relative to the pressure within thecombustion chamber so as to continuously exhaust the gases from thecombustion chamber and to exhaust the atmosphere from the space beingheated and as to draw fresh combustion air through such a supply ductfrom the exterior of the space being heated.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 isan elevation view of a spaceheater mounted on a ceiling in an overhead position according to thepresent invention.

FIG. 2 is a somewhat enlarged longitudinal section view of the heater ofFIG. 1.

FIG. 3 is an enlarged transverse section taken approximately at 3-3 inFIG. 2.

FIG. 3a is a detailed transverse section view of a modified form of theinvention and taken on a plane as indicated at 3a-3a in FIG. 3b.

FIG. 3b is a detailed longitudinal section view of the form of heaterillustrated in FIG. 3a and taken on a plane substantially as indicatedat 3b-3b in FIG. 3a.

FIG. 4 is a longitudinal section view of a modified form of spaceheater.

DETAILED DESCRIPTION OF THE INVENTION One form of the invention isillustrated in FIGS. 1 3 and comprises an elongate housing 10 having acylindrical sidewall Ill and closed ends .12 and 13. The elongatehousing 10 is maintained in an inclined position, and the inclinationmay be as much as 45 fromhorizontal. The upper end wall 13 of thehousing has a combustion gases discharging outlet 113.1 formed therein,and a stack I4 may be secured as by welding to the housing so as toreceive and carry away all the combustion gases from the outlet 13.1. Amounting bracket 15 is affixed to the housing 10 as by welding in orderto facilitate mounting of the housing at the desired location andposition so as to direct heat to the desired area.

The housing It) defines an enlarged substantially unobstructed interiorplenum 16 which defines a combustion chamber I7 adjacent the lower endof the housing,

I and a combustion gases discharging chamber 18 adja- FIG. 5 is a detailelevation view with portions thereof broken away for clarity of detailand illustrating another modified form of the invention.

cent the upper end of the housing. The combustion gases dischargingchamber is in unobstructed gas flow communication with the combustionchamber 17 and is always maintained at a superior elevation relative tothe combustion chamber 17. A radiant 19 of ceramic or similar materialhas a plurality of apertures therethrough for delivering a gas and airmixture suitable for producing a small flame at each of the aperturesand a multiplicity of the small flames across the whole flat infraredradiating face of the radiant 19. The radiant I9 is mounted on asuitable gas and air mixing housing 20 which receives the combustion airat the ports 21 and gas from the valve and pipeline 22. The gas burnerhousing 20 is mounted on the lower end wall 12 of the housing 10 and isinclined as to position so that the combustion air is delivered to theport 21 at the lower end of the housing and there is no possibility thatthe products of combustion or combustion gases from the flames will berecirculated into the ports 21. All of the products of combustionfromthe face of the radiant and the flames thereon will move upwardlytoward the top of the housing and into the combustion products deliveryand discharging chamber 18 toward the outlet 13.].

The housing 10 has an enlarged infrared and radiant heat dischargingport 23 adjacent the combustion chamber 17 and extending substantiallyone-third to one-half around the lower periphery of the cylindricalsidewall 11 beneath the radiant 19. The port 23 has a length slightlygreater than the length of the radiant l9 and the width of the port 23between the longitudinally extending side edges 23.1 is substantiallyequal to the diameter of the cylindrical sidewall 11 and significantlywider than the width of the radiant 19. It should be clear that thewidth of the infrared. discharging port 23 as measured around thetransverse periphery of the cylindrical sidewall is very significantlywider than the radiant 19 because the longitudinally extending sideedges 23.1 are both closely spaced to a diametric plane extending alongthe axis of cylindrical sidewall 11.

The upper end edge 23.2 of the infrared discharging port 23 ismaintained at a superior elevation above the lower end edge 23.3 of theport by virtue of the inclined orientation of the housing 10.

The infrared and radiant heat discharging port 23 is substantiallyclosed by a thin and flexible panel 24 of a material which is highlytransmissive of infrared and radiant heat. The panel 24 may beconstructed of a film type material known principally by its trademarkTEF- LON, which is transmissive of approximately 88 percent of infrareddirected thereto, or a polyester resin film material known principallyby its trademark MYLAR which is capable of transmitting approximately 77percent of the infrared radiation applied thereto. It is important thatthe panel 24 be highly transmissive of infrared so that an excessiveamount of heat is not accumulated in the panel as the infrared istransmitted therethrough. The known rigid forms of glass and variationsthereof, one of which is known by its trademark VICOR, areunsatisfactory to serve to close the infrared discharging port 23 andare not suitable for this invention because such material absorbssignificantly too much heat. Such rigid glass-like material cannot becooled so as to be safe to be touched while the thin flexible film typepanels 24 of the materials described are safe to touch and are capableof withstanding temperatures produced with the cooling provided.

. The film-like panel 24 is secured to the exterior of the cylindricalsidewall 11 by a spring clip 25 which is secured in the edge of thepanel 24 and which is sufficiently long as to extend around more thanhalf the periphery of cylindrical wall 11, and the resilience of therod-type bracket 25 is sufficient to grip the wall 1 1 and securelyanchor the panel 24 adjacent the lower end edge 23.3 of the periphery ofport 23. The panel 24 extends somewhat more than halfway around theperiphery of cylindrical sidewall 11, and as seen in FIGS. 1 and 3, thelongitudinally extending side edges 24.1 of panel 24 extendlongitudinally along the cylindrical sidewall 11 in spaced relation withthe side edges 23.1 of the port 23. The side edges 24.1 of the flexiblepanel 24 actually will lie flush against the exterior surface of thecylindrical sidewall 11 so as to produce a substantially sealingrelation with the housing sidewall.

The panel 24 is held away from the cylindrical sidewall 11 and away fromthe upper end edge 23.2 of the port 23, and substantially all portionsof the panel 24 except at the longitudinally extending side edges 24.1and at the anchoring bracket 25. The panel 24 is maintained in aninclined position, substantially as illustrated in FIGS. 1 and 2 by aplurality of elastic anchor cords or metal springs 26 which are securedto the panel 24 at grommets 24.2, and the cords 26 are secured to amounting bracket 27 affixed as by welding to the housing sidewall 11. Inthe form shown, the ends of the mounting bracket or rod 27 are welded tothe housing sidewall, and intermediate supporting brackets and bracesmay be provided for rod 27 as required.

The upper side or edge portion 24.3 of the flexible panel 24 ismaintained in spaced relation with the adjoining portions 11.1 of thehousing sidewall so as to cooperate therewith in defining an air passage28 for directing combustion air into the combustion chamber to provideprimary and secondary air for the fuel fired flame at the radiant.Because the air flowing through passage 28 as indicated by the arrows ais relatively cool compared to temperatures existing in the plenum l6and more specifically the combustion chamber 17, the air remains closelyadjacent and sweeps along the panel 24 so as to continuously cool theinterior surface of the panel 24, thereby cooling the entire panel 24.The passage 28 is sufficiently long and broad as to be assured that theair flow therethrough is relatively smooth and without any significantturbulence so that the air will smoothly flow into the combustionchamber and toward the port 21 and the face of the radiant 19. The panel24 is stretched taut to be free of wrinkles and to avoid causingturbulence of the flowing air.

It will be recognized that the panel 24 confronts the entire infraredand radiant heat discharging port 23, and that the panel 24 has agenerally rounded and slightly conical shape throughout the wholeportion of panel 24 which confronts the port 23. On the other hand, theradiant 19 is substantially planar in shape so that the flat front faceof the radiant from which the infrared radiates confronts varying areasof the panel 24 in varying angles of confrontation. The areas of thepanel 24 which are directly beneath the radiant 19, and lie generallyparallel to the flat radiating face of the radiant 19 are spaced amaximum distance from the radiant 19 so as to avoid excessive heating;the portions of panel 24 in the vicinity of the longitudinal side edge32.1 of the port are in the closest proximity with the radiant 19, butthe angle of confrontation of these portions of the panel 24 with theflat radiating space of the radiant 19 is very substantial and thereforea rather minimum proportion of the radiant energy is directed to thenearest areas of the panel 24.

It has been found that the combustion air moving in the direction ofarrows a sweep the flexible panel 24 of most of the dust and maintainthe panel quite clear, regardless of the dust content of the air.Essentially no significant quantity of dust is allowed to settle on thepanel 24 because of the continuous sweep of air thereacross.

In some situations it may be desirable to allow the heater 10 to operateby gravity due to the temperature of the air in the plenum 16 and theconstruction of the heater 10 which will cause the air and products ofcombustion to flow as indicated. Combustion gases may be dischargedthrough a flue to the exterior of the space being heated. It may bedesirable in certain instances to connect the outlet duct or flue 14 toa suction fan so as to produce forced flow of air and combustionproducts through the heater. As the hot combustion gases flow throughthe discharging chamber 18, the heat conductive sidewall 11 will conductaway a portion of the hear from the gases for additional heating of thespace.

Combustion gases may bedischarged into the space being heated if thespace is well ventilated as by fans. Combustion air may be also drawnfrom the space being heated.

However, it should be understood that the principal heating produced bythe heater 10 is by infrared passing through the panel 24 from radiant19.

It may be desirable to mount a heater adjacent an outside building wallW as illustrated in FIG. 4 so that the heater 10' will draw thecombustion air from the exterior E of the wall and so as to dischargethe combustion gases from the housing to a location at the exterior ofthe wall. In this form of the invention, the heater has an interiorplenum 16' defining a combustion chamber 17 and a combustion gasesdischarging chamber 18' which is disposed at a superior elevationrelative to the combustion chamber 17 and relative to the radiant 19'.In this form of the invention the combustion gases discharging flue duct14' may be extended horizontally through the wall W. The flexible TEFLONor MYLAR infrared transmissive panel 24' is laid against the exterior ofthe housing sidewall 11' around the entire periphery of the infrareddischarging port 23'. The combustion air is brought through a duct whichextends through the wall W and draws air from the exterior E. The duct30 incorporates an air flow smoothing plenum chamber 31 which dischargesdirectly into the plenum 16' adjacent the upper edge of the flexiblepanel 24' so as to cause the incoming combustion air to flow through theinlet 32 and cool the panel 24' as previously described. This heater 10'is completely sealed as relates to the spaces at the interior side ofwall W which are to be heated so as to minimize the entrance of dustinto the heater and to minimize the exposure of the flame to theatmosphere within the space.

In the form of heater illustrated in FIGS. 5, 6 and 7, the heater 10.1has a construction substantially identical to that illustrated in FIGS.1 3. In this form of the invention, the flexible panel 24a is arrangedin relation to the infrared and radiant heat discharging port 23a in thesame fashion as described in connection with FIGS. 1 3. In addition, thepanel 24 is formed integrally of and merges into a duct 24a of the sameTEF- LON material which is clamped or connected at 35 to an air supplyduct 36 which may be formed of any suitable material such as rigid metalor polyethylene, or any other suitable duct-type material. The TEFLONduct 24a is laid against the lower side of the housing sidewall and hasan edge 24b secured to the heater housing sidewall adjacent the upperend edge of the infrared discharging port 23a so as to entirely seal theTEFLON duct 24a to the heater housing 10.1.

This form of heater illustrated in FIGS. 5 7 may be connected to aconventional flue or discharge duct, or this heater may dischargecombustion gases directly into the space being heated in which case thespace must be operated under negative pressure under influence of a fanwhich continuously draws air and combustion gases out of the space beingheated. The combustion air may be supplied from the duct 36 from alocation outside the space being heated, such as the exterior of thebuilding. In the form of the invention illustrated in FIGS. 8 and 9, theheater 10.2 is essentially identical to identical to that illustrated inFIGS. 1 3. However, in this form of the invention, an air baffle 37 ismounted within the housing at a location adjacent the end edge of theinfrared discharging port 23 so as to prevent combustion gases fromflowing downwardly along the infrared transmissive panel 24 andcommingling with these combustion gases for recirculation to the flameheated radiant 19.

In the form of invention illustrated in FIGS. 3a and 4a, the heater 10.3is substantially the same as illustrated in FIGS. 1 3 with the exceptionthat the housing 11.3 has a substantially square or rectangulartransverse shape. The thin flexible panel 24.3 is stretched taut acrossthe open bottom of the housing which defines the infrared dischargingport 23.3; and the Teflon flexible panel 24.3 is drawn tightly acrossthe rounded lower edges of the sidewalls 11.30: of the housing, and theTeflon panel 24.3 is secured by a suitable bracket or anchor to onesidewall of the housing and is held secure at the other side of thehousing by an elastic cord or spring 33.3 which is detachably secured toan anchor element such as hook 34.3 on the side of the housing. Thehousing 10.3 has an air supply duct and plenum 35.3 formed integrallythereof or affixedly secured thereto as illustrated in FIG. 3b.Combustion air is delivered through the duct and plenum 35.3 to theupper side edge of the Teflon panel 24.3 so that the air flows smoothlyacross the Teflon panel] and then upwardly into the combustion chamber17.3. It will be seen that the Teflon panel 24.3 is also stretched in alongitudinal direction of the heater 10.3 by an elastic cord or spring.

26.3 which is secured as by grommets to one end edge of the Teflon panel24.3 and is detachably secured to an anchor 26.3a on the end wall of thehousing. This form illustrated in FIGS. 30 and 3 b is particularly welladapted to bringing air into the heater 10.3 from an exterior location,because the rectangular or square transverse configuration lends itselfto easy attachment of the combustion air delivery duct and plenum 35.3.

The air delivery passage 28.3 defined between the upper side edgeportion of the Teflon panel 24.3 and the bottom wall 11.3b of thehousing extends entirely across the width of the housingwithoutinterruption or interference so that there is essentially noinfluence which would tend to cause turbulence in the flow of airsweeping downwardly across the taut panel 24.3 for cooling of the paneland supplying combustion air to the radiant.

It will be seen that I have provided a new and improved fuel fired spaceheater directing infrared in a downward direction from a radiantconfined within a combustion chamber adjacent the lower end of anelongate and inclined housing and downwardly through a flexible panel ofmaterial highly transmissive of infrared wherein the panel is drawn tautacross a large radiant heat and infrared discharging portin the lowerside of the housing. An air inlet is provided adjacent the upper edge ofthe inclined flexible panel to provide combustion air for the fuel firedradiant and to continu ously cool the flexible panel of infraredtransmissive material as the inwardly flowing combustion air flowssmoothly downwardly across the panel.

What I claim is:

1. A fuel fired space heater, comprising:

a flame heated radiant facing generally downwardly and directinginfrared downwardly for heating such a space;

an elongate enclosed housing defining a plenum chamber having acombustion portion encompassing said radiant and also having acombustion gases discharging portion adjacent to and at a superiorelevation relative to said combustion portion, said discharging portionbeing in open and direct gas flow communication withthe combustionportion of the plenum chamber, and the housing having a combustion gasesdischarging outlet communicating with the gases discharging portion ofthe plenum chamber and said outlet also being at a superior elevationrelative to the combustion portion of the plenum chamber, the housingalso having downwardly facing radiant heat discharging port disposedbelow said radiant and below the combustion portion of the plenumchamber, there being one lower side of the periphery of the portdisposed at a lower elevation than the opposite upper side of theperiphery of the port;

a thin flexible inclined panel of material highly transmissive ofinfrared and confronting and obstructing the entire radiant heatdischarging port, the side portions of the panel being in close fittingand substantially sealing relation with the sides of the periphery ofthe radiant heat discharging port, the upper end of the inclined panelbeing in spaced and confronting relation with and beneath the housingadjacent the upper side of the periphery of the radiant heat dischargingport and cooperating with the housing to define a combustion air inlet,the inner face of the flexible panel being inclined downwardly from saidupper side portion and across the radiant heat discharging port to beswept clear of dust and continuously cooled by incoming combustion airbeing supplied from the inlet to the radiant; and

means securing said flexible panel to the housing.

2. The space heater according to claim 1 and the radiant heatdischarging port being broad and exceeding the size of the radiant.

3. The space heater according to claim 1 and the housing being inclinedand having upper and lower end portions, the radiant and the radiantheat discharging port being disposed adjacent the lower end portion, andthe gases discharging outlet being disposed adjacent the upper endportion of the housing.

4. The space heater according to claim 3 wherein the inclined housingand the inclined flexible panel are inclined in the same direction, thehousing having an inclination at least as steep as the panel.

5. The space heater according to claim 1 wherein the housing has arounded transverse shape, the radiant heat discharging port extendingtransversely through a significant portion of the housing periphery, theflexible panel having a rounded transverse shape similar to thetransverse shape of the housing.

6. The space heater according to claim 1 wherein the housing has arectangular transverse shape, the radiant heat discharging portextending transversely across the bottom of the housing, and theflexible panel being pulled taut across the port.

7. The space heater according to claim 5 and the flexible panel beingtaut in the longitudinal direction to smoothly directing combustion airflowing thereover.

8. The space heater according to claim 5 and the radiant having adownwardly facing and substantially flat flame heated radiating face,the spacing and angle of confrontation between various areas of thetransversely rounded flexible panel and the flat radiating face of theradiant varying to vary the infrared applied to and through the panel.

9. The space heater according to claim 1 and a combustion air supplyduct connected with said air inlet.

10. The space heater according to claim 9 and said duct being formedintegrally of and in one piece with said flexible panel.

11. The space heater according to claim 9 and said duct incorporating aplenum chamber adjacent the air inlet and smoothing the flow ofcombustion air across the panel.

12. The space heater according to claim 1 and resiliently stretchablemeans securing the flexible panel to the housing and drawing the paneltaut across the radiant heat discharging port.

13. The space heater according to claim 5 and resiliently stretchablemeans on the housing and connected to the upper end of the flexiblepanel and extending longitudinally of the elongate housing and drawingthe panel taut across the port.

14. A fuel space heater, comprising:

a flame heated source of infrared;

a housing defining a combustion chamber with said source of infraredconfined therein, the housing also having a heat exchange chamberadjacent to, above and in open gas flow communication with thecombustion chamber, the housing having walls of heat-conductive materialadjacent the heat exchange chamber, the housing having an infrareddischarge port opening in a downward direction from the combustionchamber, and a combustion air inlet adjacent one side of the port; and

an inclined panel of infrared translucent material underlying andobstructing said port, one upper edge portion of the inclined panelbeing disposed adjacent said air inlet to receive cooling air downwardlyacross the inclined panel.

V UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No, 3, 424r Dated Invenmfls) J hn E Eich-enlaub It is certified that error appearsin the above-identified patent and that said Letters Patent are herebycorrected as shown belpw:

In Claim 14, line 29, after "fuel" insert-fire d-'.

Signedv and sealed this 2nd day of 'July 1974,-

sBALj Attest: e

EDWARD M, FLETCHBRJR. QMARSHALL' DANN Attesting. Officer Commmis'sionerof Patents FORM nap-1050 (10,59)

1. A fuel fired space heater, comprising: a flame heated radiant facinggenerally downwardly and directing infrared downwardly for heating sucha space; an elongate enclosed housing defining a plenum chamber having acombustion portion encompassing said radiant and also having acombustion gases discharging portion adjacent to and at a superiorelevation relative to said combustion portion, said discharging portionbeing in open and direct gas flow communication with the combustionportion of the plenum chamber, and the housing having a combustion gasesdischarging outlet communicating with the gases discharging portion ofthe plenum chamber and said outlet also being at a superior elevationrelative to the combustion portion of the plenum chamber, the housingalso having downwardly facing radiant heat discharging port disposedbelow said radiant and below the combustion portion of the plenumchamber, there being one lower side of the periphery of the portdisposed at a lower elevation than the opposite upper side of theperiphery of the port; a thin flexible inclined panel of material highlytransmissive of infrared and confronting and obstructing the entireradiant heat discharging port, the side portions of the panel being inclose fitting and substantially sealing relation with the sides of theperiphery of the radiant heat discharging port, the upper end of theinclined panel being in spaced and confronting relation with and beneaththe housing adjacent the upper side of the periphery of the radiant heatdischarging port and cooperating with the housing to define a combustionair inlet, the inner face of the flexible panel being inclineddownwardly from said upper side portion and across the radiant heatdischarging port to be swept clear of dust and conTinuously cooled byincoming combustion air being supplied from the inlet to the radiant;and means securing said flexible panel to the housing.
 2. The spaceheater according to claim 1 and the radiant heat discharging port beingbroad and exceeding the size of the radiant.
 3. The space heateraccording to claim 1 and the housing being inclined and having upper andlower end portions, the radiant and the radiant heat discharging portbeing disposed adjacent the lower end portion, and the gases dischargingoutlet being disposed adjacent the upper end portion of the housing. 4.The space heater according to claim 3 wherein the inclined housing andthe inclined flexible panel are inclined in the same direction, thehousing having an inclination at least as steep as the panel.
 5. Thespace heater according to claim 1 wherein the housing has a roundedtransverse shape, the radiant heat discharging port extendingtransversely through a significant portion of the housing periphery, theflexible panel having a rounded transverse shape similar to thetransverse shape of the housing.
 6. The space heater according to claim1 wherein the housing has a rectangular transverse shape, the radiantheat discharging port extending transversely across the bottom of thehousing, and the flexible panel being pulled taut across the port. 7.The space heater according to claim 5 and the flexible panel being tautin the longitudinal direction to smoothly directing combustion airflowing thereover.
 8. The space heater according to claim 5 and theradiant having a downwardly facing and substantially flat flame heatedradiating face, the spacing and angle of confrontation between variousareas of the transversely rounded flexible panel and the flat radiatingface of the radiant varying to vary the infrared applied to and throughthe panel.
 9. The space heater according to claim 1 and a combustion airsupply duct connected with said air inlet.
 10. The space heateraccording to claim 9 and said duct being formed integrally of and in onepiece with said flexible panel.
 11. The space heater according to claim9 and said duct incorporating a plenum chamber adjacent the air inletand smoothing the flow of combustion air across the panel.
 12. The spaceheater according to claim 1 and resiliently stretchable means securingthe flexible panel to the housing and drawing the panel taut across theradiant heat discharging port.
 13. The space heater according to claim 5and resiliently stretchable means on the housing and connected to theupper end of the flexible panel and extending longitudinally of theelongate housing and drawing the panel taut across the port.
 14. A fuelspace heater, comprising: a flame heated source of infrared; a housingdefining a combustion chamber with said source of infrared confinedtherein, the housing also having a heat exchange chamber adjacent to,above and in open gas flow communication with the combustion chamber,the housing having walls of heat-conductive material adjacent the heatexchange chamber, the housing having an infrared discharge port openingin a downward direction from the combustion chamber, and a combustionair inlet adjacent one side of the port; and an inclined panel ofinfrared translucent material underlying and obstructing said port, oneupper edge portion of the inclined panel being disposed adjacent saidair inlet to receive cooling air downwardly across the inclined panel.